Apparatus for the manufacture of artificial materials



Jan. 3, 1939.

R. w. MONCRIEFF ET AL 2,910

APPARATUS FOR THE MANUFACTURE OF ARTIFICIAL MATERIALS Origipal Filed April 19, 1935 ROBERT W MONCRIEFF FRANK B- HLt I NV em-ons ATIDRNEYS atented den. 3, 1939 mac STATES PATENT orrlcr.

APPARATUS FOR THE MANUFACTURE OF ARTIFICIAL MATERIALS tion of Delaware Original application Apr-i119, 1935, Serial No.

17, 1936, Serial No. 69,282.

May 30, 1934 9 Claims.

This application is a divisional application from our application S. No. 17,242 and relates to improved apparatus for the treatment of filaments,

threads, foils and similar materials with fluid media under pressure.

In U. S. application S. No. 4,510 filed February 1, 1935, processes are described wherein filaments, threads, foils and similar materials having a basis of cellulose acetate or other cellulose derivative are passed through a chamber containing steam under pressure and are stretched while in the chamber. In this manner, materials having increased tensile strength may be obtained in a very simple manner.

As indicated in the said specification, the orifices for the passage of the materials into and out of the pressure stretching chamber are preferably as small as-possible so as to minimize escape of steam. Across these orifices, there is a pressure drop and the steam escaping exerts a frictional effect on the materials passing through the orifices, thereby setting up in the materials a tension additional to the tension exerted by any mechanical stretching devices.

As indicated in the said specification, it is preferable that the condition of the steam be such as to enable the stretching to be carried out with as low a stretching tension as possible.

Not only does the stretching tension afiect to some extent the properties of the stretched product such as tensile strength and extension, but, in addition, with too high a stretching tension, breakage of the filaments, threads or the like is apt to occur. We have found that for the best results, especially when high degrees of stretch are required, for example degrees of stretch exceeding 500% of the original length of the thread, the tension exerted by the escaping steam on the threads entering the steam chamber is too high,

and the presentinvention has for its object to reduce this tension on the incoming threads, apart from other objects to be referred to hereinafter.

We have found that by providing a compressed air chamber in front of the steam stretching chamber and by locating nip rollers or other feed device in the compressed air chamber,-the tension exerted on the threads in the steam chamber by the steam escaping from the thread inlets is reduced. The flow of steam across the inlet orifices is dependent on the drop of pressure across these orifices and by maintaining the air in the compressed air chamber at substantially the same pressure as the steam in the stretching chamber, flow is practically avoided, and

Divided and this application March In Great Britain tension upon the threads during the stretching treatment, due to escape of steam through the inlet orifices, is substantially eliminated.

Thus, in the new process, cellulose acetate threads may be passed through suitable orifices in one side of a compressed air chamber into substantially non-slipping contact with nip rollers or other feed device located in the compressed air chamber, thence through further orifices into the stretching chamber containing saturated or wet steam under pressure, out of orifices at the far end of the steam chamber and thence into substantially non-slipping contact with nip rollers or other stretching device-located beyond the stretching chamber. By maintaining the air in the compressed air chamber at the same pressure as the steam in the stretching chamber, tension on the threads due to the escape of steam from the thread inlets to the stretching chamber is entirely eliminated. It is desirable, however, to avoid air entering the stretching chamber from the compressed air chamber, and accordingly it is preferable to maintain the air in the compressed air chamber at a slightly lower pressure than the steam in the stretching chamber so that a small escape of steam into the compressed air chamber takes place but insufficient to give rise to any substantial tension in the threads.

The tension on the threads due to escape of steam from the thread outlet orifices from the stretching chamber may be much smaller than the tension exerted on the threads entering the steam chamber by the steam escaping from the thread inlets in the absence of the compressed air chamber, since at the outlet end of the steam chamber the threads are travelling in the same direction as the steam and may, since they have been stretched, be travelling at quite a high speed, whereas at the thread inlet the threads are travelling in a direction opposite to that of the escaping steam. However, if desired, the tension exerted by the escaping steam on the threads passing through the outlets from the stretching chamber may be reduced or eliminated by the provision of a second compressed air chamber containing a feed device, which may in this case be the stretching device, at the outlet end of the stretching chamber.

The chamber located at one or both ends of the travel of the threads through the steam chamber may contain, instead of compressed air, any other compressed gas or fluid inert to the materials under treatment.

The invention is applicable to any treatment of filaments, threads or the like or of foils or other web materials with fluid media under pressure where it is desired to run the materials continuously through a pressure treatment chamber and to reduce or eliminate tension upon the materials across the inlets or outlets.

For convenience the chambers located at one or both ends of the travel of the threads or other materials through the treatment chamber will be referred to as end pressure chambers, though this term is not to be understood as connoting that the treatment chamber is necessarily extended in the general direction of travel of the threads or other materials therethrough.

The new apparatus comprises a pressure treatment chamber with an inlet for the treatment fluid in combination with an end pressure chamber with an inlet for inert fluid and containing a feed device for the materials and communicating with the treatment chamber, the appa- I ratus having inlet and outlet orifices opening to the outer air to permit passage of the materials through the chambers in succession but being substantially closed to permit the develop-- ment of fluid pressure therein.

As previously indicated, the apparatus may comprise an end pressure chamber containing a feed device for the materials disposed at each end of the travel of the materials through the treatment chamber.

The treatment chamber may be provided with a pressure gauge, a pressure relief valve and, where steam is the fluid treatment medium, a steam trap or other device for withdrawing condensate from the steam chamber. In addition, the end pressure chamber may be provided with a pressure gauge and pressure relief valve and,

if there is escape of steam into the chamber, with a steam trap or similar device.

In addition to reducing the tension exerted on the threads at the inlet and outlet orifices of the treatment chamber, the provision of the pressure chamber at both ends of the treatment chamber serves to prevent escape of the fluid treatment medium. This is'of considerable advantage where the fluid medium is a gas or liquid, the escape of which is objectionable, or where it is desirable for economic reasons to prevent loss of the medium.

Other applications of the apparatus of the present invention include saponiflcation of cellulose ester threads, foils or similar materials under pressure, for example by means of caustic soda, ammonia, methylamine or ethylene diamine, as described in U. S. application S. No. 11,080 flled March 14, 1935, or stretching operations carried out by means of hot water under pressure as described in U. S. application S. No. 4,511 filed February 1, 1935, or by means of organic softening agents under pressure as described in U. S. application S. No. 11,079 flled March 14, 1935.

Where the object is purely to prevent loss of the fluid treatment medium, and the tension on the thread or other material is immaterial, it is unnecessary to provide feed devices in the end pressure chambers. Thus, in a pressure saponiflcation treatment where escape of saponifying medium into the outer atmosphere is not desirable and at the same time the tension exerted by the fluid medium at the inlets and outlets for the threads or other materials is of nomoment, the apparatus may consist of a pressure treatment chamber, and two end pressure chambers communicating respectively with the inlet and outlet orifices of the treatment chamber and without feed devices therein.

On the other hand where it is desired to pre vent escape of the fluid treatment medium and the tension exerted by the flow of treatment medium across the orifices for the passage of the threads or other materials into and out of the treatment chamber is only of moment at the inlet, the apparatus may comprise a pressure treatment chamber provided at one end with an end pressure chamber containing a feed device for the materials and at the other end with a second end pressure chamber without a feed device therein.

The accompanying drawing illustrates diagrammatically some forms of apparatus in accordance with the present invention,

Fig. 1 being a longitudinal cross-section of an apparatus suitable for stretching cellulose acetate threads in steam,

Fig. 2 a cross-section (to a larger scale) on the line 22 of Fig. 1,

Fig. 3 a longitudinal cross-section of another form of apparatus suitable for stretching cellulose acetate threads in steam, and

Fig. 4 a longitudinal cross-section of an apparatus suitable for the treatment of threads of cellulose acetate under pressure with a fluid such as an organic softening agent for stretching or an organic amine solution for saponiflcation wherein loss of the active agent is to be avoided.

Referring to Figs. 1 and 2, the threads I from a creel of bobbins 2 pass through small orifices 3 into a compressed air chamber 4 in non-slipping contact with nip rollers 5 in the compressed air chamber, through small orifices 6 into a steam chamber 1, out of the steam chamber through orifices 8, in non-slipping contact with nip rollers 9 for stretching, and are finally wound on a creel of bobbins ID. The compressed air is introduced through the inlet I I into the chamber 4 which is provided with a pressure gauge 'I2, a pressure relief valve l3, and a steam trap 14. Steam enters through perforated pipes l5 so positioned that wet or saturated steam is dirested on to the threads immediately on their entry into the steam chamber 1. The chamber 1 is also provided with a pressure gauge IS, a pressure relief valve l1, and a drain I8 for condensate.

In Fig. 3, the stretching rollers 9 are located in a second compressed air chamber l9 out of which the threads pass by orifices 20 to the take-up device. The compressed air chamber is is provided with a pressure gauge 2|, a pressure relief valve 22, and a drain23 for condensate, and is filled with compressed air through the inlet 24.

For the general conditions of the steam stretching operation, reference is made to U. S. application S. No. 4,510. By means of the present invention very much higher degrees of stretch are obtainable than without the use of the end pressure chamber. By treating cellulose acetate threads with wet or saturated steam at the appropriate temperature and pressure in accordance with the present invention, stretches of over 2000% of the original length of the threads are obtainable and, moreover, the qualities of the thread such as tensile strength and extensibility appear to be beneficially affected by the use of the end pressure chamber.

The apparatus illustrated in Figs. 1 and 3 may also be used for stretching cellulose acetate threads in hot water by providinginstead of the steam inlets l5, an inlet and outlet for the water and a heater in the chamber I, as illustrated in the drawings accompanying U. S. application S. No. 4,511. For the conditions for hot water stretching, reference is made to this specification.

Referring to Fig. 4, which is an apparatus suitable for example for stretching in an organic solvent or for saponification of threads of cellulose acetate, the threads I pass through the orifices 3 into a compressed air chamber 4 after passing in non-slipping contact with the nip rollers 5. From the compressed air chamber 4, they pass through orifices 6 into the pressure treatment chamber 1, and thence through orifices 8 into a second compressed air chamber l9 and through orifices 20 into substantially nonslipping contact with nip rollers 9. The compressed air chamber IQ is provided with a pressure gauge 2i, a pressure relief valve 22 and an inlet 24 for compressed air. The treatment fluid enters the pressure treatment chamber I by the inlet 25.

In a modification of the invention the end pressure chamber, instead of being provided with nip rollers or other feed device for the materials, may contain a bobbin, cheese, roll or other package adapted to supply the material to the pressure treatment chamber. The terms device for delivering the materials and delivery device in the appended claims are used generi-- cally to include such packages as well as feed devices, and the 'term feed devices for the materials excludes the packages and includes only nip rollers or similar devices for forwarding the running materials. The use of packages in the end pressure chambers permits of batches of material being subjected to treatment with fluid media under pressure. It will be apparent howouter air. I

What we claim and desire to secure by Letters Patent is:

1. Apparatus for subjecting running threads, foils and similar materials to treatment with fluid media under pressure, comprising in combination a pressure treatment chamber with an inlet for the treatment fluid, an end pressure chamber with an inlet for inert fluid and containing a positively driven feed device for the materials and communicating with the treatment chamber, said end pressure chamber being adapted to be maintained at a pressure difierent from that in the pressure treatment chamber, and a forwarding device for drawing the materials through the treatment chamber, the apparatus having inlet and outlet orifices opening to the outer air to permit passage of the materials through the chambers in succession but being substantially closed to permit, the development of fluid pressure therein, the said feed device, forwarding device and intervening orifices for passage of the materials being adapted to permit passage of the materials between the feed device and the forwarding device along a path lying substantially in one plane.

2. Apparatus for stretching running threads,

foils and similar materials in the presence of steam under pressure, comprising in combination a pressure steam chamber, means associated with said chamber for creating an atmosphere of steam under pressure in said chamber, an end pressure chamber with an inlet for compressed air and containing a positively driven feed device for the materials and communicating with the steam chamber, said end pressure chamber being adapted to be maintained at a pressure difierent from that in the pressure steam chamber, and a positively driven stretching debetween the feed and stretching devices along a path lying substantially in one plane.

3. Apparatus for stretching running threads and similar materials in the presence of steam under pressure, comprising in combination an end pressure chamber with an inlet for compressed air and containing a positively driven feed device for the materials, a pressure steam chamber communicating with the said end pressure chamber, said end pressure chamber being adapted to be maintained at a pressure different from that in the pressure steam chamber, means associated with said steam chamber for introducing steam into said chamber and directing it on to the materials immediately after their entry into said chamber from the end pressure chamber, and a positively driven stretching 'device for stretching the materials in said steam chamber, the apparatus having inlet and outlet orifices opening to the outer air to permit passage of the materials through the chambers in succession but being substantially closed to permit the development of fluid pressure therein.

4. Apparatus for stretching running threads, foils and similar materials in the presence of steam under pressure, comprising in combination a pressure steam chamber free from forwarding devices, means associated, with said chamber for creating an atmosphere of steam under pressure in said chamber, an end pressure chamber with an inlet for compressed air 'mit the development of fluid pressure therein,

said feed device, stretching device and intervening orifices for passage of the materials being adapted to'permit passage of the materials between the feed and stretching devicesalong a path lying substantially in one plane.

5. Apparatusfor subjecting running threads,

foils and similar materials to treatment with fluid media under pressure, comprising in combination a pressure treatment chamber with an inlet for treatment fluid,.an end pressure chamber associated with said treatment chamber, having an inlet for inert fluid and containing a positively driven feed device for the materials, a second end pressure chamber with an inlet for inert fluid and associated with said treatment chamber and a positively driven forwarding device, the end pressure chambers being adapted to be maintained at a pressure different from that in the pressure treatment chamber and having orifices opening to the outer air and communicating with the treatment chamber to permit passage of the materials from the outer air first through one end chamber, then through the treatment chamber, next through the other end chamber and finally into the outer air again, said feed device, forwarding device and intervening orifices for passage of the materials being adapted to permit passage of the materials between the feed and forwarding devices along a path lying substantially in one plane, and the apparatus being substantially closed to permit the development of fluid pressure therein.

6. Apparatus for subjecting running threads, foils and similar materials to treatment with fluid media under pressure, comprising in com- .bination a pressure treatment chamber with an inlet for treatment fluid and free from forwarding devices, an end pressure chamber associated with said treatment chamber, having an inlet for inert fluid and containing a positively driven feed device for the materials, a second positively driven feed device for drawing the materials through the treatment chamber, and a second end pressure chamber with an inlet for inert fluid and associated with said treatment chamber, the end pressure chambers being adapted to be maintained at a pressure different from that in the pressure treatment chamber and having orifices opening to the outer air and communicating with the treatment chamber to permit passage of the materials from the outer air first through one end chamber, then through the treatment chamber, next through the other end chamber and finally into the outer. air again, the apparatus being substantially closed to permit the development of fluid pressure therein.

7. Apparatus for subjecting running threads, foils and similar materials to treatment with fluid media under pressure, comprising in combination a pressure treatment chamber with an inlet for treatment fluid, an end pressure chamber, associated with said treatment chamber, having an inlet for inert fluid and containing a positively driven feed device for the materials, and a second end pressure chamber, having an inlet for inert fluid, associated with said treatment chamber and containing a positively driven feed device for the materials adapted to stretch the materials in the pressure treatment chamber, the end pressure chambers being adapted to be maintained at a pressure diiferent from that in the pressure treatment chamber and having orifices opening to the outer air and communicating with the treatment chamber to permit passage of the materials from the outerair first through one end chamber, then through the treatment chamber, next through the other end chamber and finally into the outer air again, said feed devices and intervening orifices for passage of the materials being adapted to permit passage of the materials between the feed devices along a path lying in one plane, the apparatus being substantially closed to permit the development of fluid pressure therein.

8. Apparatus for stretching running threads and like materials in the presence of steam under pressure, comprising in combination a pressure steam chamber, means associated with said chamber for introducing steam and directing it on to the materials immediately after their entry into said chamber, an end pressure chamber, associated with said steam chamber, having an inlet for inert fluid and containing a positively driven feed device for the materials, and a second end pressure chamber, having an inlet for inert fluid, associated with said steam chamber and containing a positively driven feed device for the materials adapted to stretch the materials in the pressure steam chamber, the end pressure chambers being adapted to be maintained at a pressure difierent from that in the pressure steam chamber and having orifices opening to the outer air and communicating with the steam chamber to permit passage of the materials from the outer air first through one end chamber, then through the steam chamber, next "through the other end chamber and finally into the outer air again, the apparatus being substantially closed to permit the development of fluid pressure therein.

9. Apparatus for stretching running threads and like materials in the presence of steam under pressure, comprising in combination a pressure steam chamber free from forwarding devices, means associated with said chamber for introducing steam and directing it on to the materials immediately after their entry into said chamber, an end pressure chamber, associated with said steam chamber, having an inlet for inert fluid and containing a positively driven feed device for the materials, and a second end pressure chamber, having an inlet for inert fluid, associated with said steam chamber and containing a positively driven feed device for the materials adapted to stretch the materials in the pressure steam chamber, the end pressure chambers being adapted to be maintained at a pressure different from that in the pressure steam chamber and having oriflces opening to the outer air and communicating with the steam chamber to permit passage of the materials from the outer air first through one end chamber, then through the steam chamber, next through the other end chamber and finally into the outer air again, the apparatus being substantially closed to permit the development of fluid pressure therein.

ROBERT WIGHTON MONCRIEFF. FRANK BRENTNALL HILL. 

